Flame retardant pile fabric

ABSTRACT

A FLAME RETARDANT PILE FABRIC IS PROVIDED. A FIBROUS LAYER COMPOSED OF COMBUSTIBLE FILAMENTS OR FIBERS EXTENDS FROM THE TOP SURFACE OF A FIBROUS BACKING TO PRESENT A PILE SURFACE. A COATING OF A FILM FORMING HALOGEN-CONTAINING POLYMER AND A WATER-INSOLUBLE ORGANO-PHOPHOROUS COMPOUND IS PPLIED TO AND CONFINED ESSENTIALLY TO THE TOP SURFACE   OF THE BACKING. WHERE THE BACKING IS MADE IN THE MAIN OF A THERMOPLASTIC MATERIAL, A COATING OF THE HALOGEN-CONTAINING POLYMER WITHOUT THE ORGANO-PHOSPHOROUS COMPOUND RENDERS THE FABRIC SUFFICIENTLY FLAME RETARDANT.

'March 6, 1973 D. H. MARTIN ,1 9,

FLAME RETARDANT PILE FABRIC Filed D60. 9, 1970 INVENTORS DONALD H.MARTIN DONALD A. HOLMER DENNIS J. DURANT ROLAND J. BRYAN, JR.

JAMES H. SAUNDERS WILLIAM B. BLACK BY ,dm p 2. 7m

ATTORNEY United States Patent O 3,719,547 FLAME RETARDANT PILE FABRICDonald H. Martin, Gulf Breeze, and Donald A. Holmer, Dennis J. Durant,Roland J. Bryan, Jr., James H. Saunders, and William B. Black,Pensacola, Fla., assignors to Monsanto Company, St. Louis, Mo.

Filed Dec. 9, 1970, Ser. No. 96,403 Int. Cl. D03d 27/00; D04h 11/00 US.Cl. 161-67 5 Claims ABSTRACT OF THE DISCLOSURE A flame retardant pilefabric is provided. A fibrous layer composed of combustible filaments orfibers extends from the top surface of a fibrous backing to present apile surface. A coating of a film forming halogen-containing polymer anda water-insoluble organo-phosphorous compound is applied to and confinedessentially to the top surface of the backing. Where the backing is madein the main of a thermoplastic material, a coating of thehalogen-containing polymer without the organo-phosphorous compoundrenders the fabric sufliciently flame retardant.

BACKGROUND OF THE INVENTION The reduction of the flammability of pilefabrics prepared from cellulosic and synthetic filaments and fibers haslong been the subject of much research effort. Continuing search is madefor ways to render such fabrics less flammable. Many improvements towardthis end have been made. However, two recent innovations in pile fabrichave increased the flammability thereof such that prior procedures forreducing the flammability are no longer entirely suitable. In oneinstance there is a recent increased consumer demand for carpets of shagconstruction. The

long, coarse nap on the surface of a shag carpet provides an environmentfor flame propagation. Also, to render carpets having a pile ofsynthetic fibers antistatic and soil resistant, it is common practice inmost recent times to incorporate relatively large amounts ofpolyalkoxylated compounds. These additives are wax-like and per se areflammable. A fire hazard exists where a shag carpet is made of pilefibers having polyalkoxylated compounds to reduce the static build-upand soiling.

Surprisingly, the present invention provides a flame-retardant carpeteven in most shag constructions wherein the pile filaments or fibershave anti-static quantities of polyalkoxylated compounds incorporatedtherein.

SUMMARY OF THE INVENTION The flame-retardant pile fabric structuredescribed herein is composed of a fibrous layer composed of normallycombustible filaments or fibers made from synthetic polymers orcellulose based materials including cotton, rayon, cellulose acetate andthe like. This layer may be a yarn pile preferably made of a syntheticpolymer including polyester, polyamide, modacrylic and polyolefins. Mostpreferably, the pile yarn is made of polyamide (particularly nylon-66 ornylon-6) and contains an antistatic quantity of a combustible wax-likesubstance. The pile yarn is secured in a primary backing by tufting,flocking, weaving, or the like. On the pile side of the backing there isapplied a thin coating composed of an intimate mixture of a filmforminghalogen-containing polymer and a Water-insoluble organo-phosphorouscompound. The phosphorous compound is a plasticizer of polyvinylchloride and of polyvinylidene chloride. The coating is essentiallyconfined to the top surface of the backing. Optionally, the pile fabricstructure has a secondary backing of conventional construction. Forbacking made of thermoplastic material an 3,719,547 Patented Mar. 6,1973 "ice application of a halogen-containing polymer alone willsuffice. The structure has a high degree of resistance to ignition andburning and has a low level of flammability or flame spread. A method ofmaking the pile fabric structure is provided.

DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE INVENTION Theprimary carpet backing is made from suitable material. It is be aconventional woven jute construction. Also, the backing may be made of anon-woven fibrous mass made of cellulosic or non-cellulosic materialincluding nylon, polyester, and polyolefin. Backing constructed fromtwistless flat ribbons of synthetic filaments or ribbon-like materialscan be used. Other fabric backing structures likewise can be used.

The film-forming polymer ingredient of the topside applied emulsion,plastisol, solution, or latex is composed in the main of ahalogen-containing polymer which includes polymeric vinyl halide,polymeric vinylidene halide or c0- polymers thereof. An additional andparticularly convenient form in which to apply plastisols is a foamedproduct. By film forming is meant the ability to form films by airdrying a deposited coating or by coalescing or agglomerating the polymerlatex with subsequent fusion. Minor amounts of other monoethylenicallyunsaturated compounds such as vinyl acetate, acrylonitrile, and the likemay be copolymerized with vinyl halide and/ or vinylidene halide toprovide a suitable film-forming polymer. The amount of the non-halidecomonomer is variable depending on the particular monomers employed andon the fabric structure However, increasing the amount of nonhalidecomonomer results in reducing the flame retardant properties. Therefore,selection is made with regard to flame retarding properties of thepolymer produced and the fabric structure desired. Especially useful arepolymeric vinyl chloride, polymeric vinylidene chloride, and copolymersthereof. A very useful range of copolymers are those containing from 10to 20 percent of vinyl chloride copolymerized with 90 to percentvinylidene chloride. Chlorine-containing polymers derived from dienes,e.g. polychloroprene, chlorinated rubber and rubber hydrochloride aresuitable but to a lesser degree. In place of the chlorine compoundsdescribed, there may be used the corresponding bromine or iodinecompounds, as well as co polymers thereof, provided they arefilm-forming.

The polyvinyl chloride plasticizers incorporated into the film-formingmaterial applied to the topside of the primary backing may be anysuitable organo-phosphorous compound. Preferred are phosphate esters ofthree general classes: trialkyl phosphates, triaryl phosphates, andmixed alkyl aryl pohsphates. These orthophosphate esters conform to theformula wherein R R and R are the same or different monovalent radicalsselected from the group consisting of an aliphatic radical of 1-24carbon atoms, an alicyclic radical and an aromatic radical. R R and Rmay or may not be halogenated. Preferably R is a branched chain alkylradical terminating with a CH group and containing at least 6 and notmore than 15 carbon atoms and R and R are phenyl radicals. Among thetriaryl esters are tricresyl phosphate, triphenyl phosphate, diphenylcresyl phosphate, diphenyl xylyl phosphate, tritolyl phosphate. Amongthe trialkyl phosphate esters are tri(n-octyl)phosphate,tri(2-ethylhexyl)phosphate, triethyl phosphate, tributyl phosphate,tri(dichloropropyl)phosphate, trichloroethyl phosphate, tributoxyethylphosphate. The preferred orthophosphate esters are triaryl phosphatesand alkyl diaryl phosphate, the latter class of phosphates beingpreferred. Among the dialkyl monoaryl phosphates are di-(2-ethylhexyl)phenyl phosphate, di(n-butyl)cresyl phosphate, etc. Amongthe alkyl diaryl phosphates are methyl diphenyl phosphate, ethyldiphenyl phosphate, propyl diphenyl phosphate, n-butyl diphenylphosphate, Z-methylpropyl diphenyl phosphate, 2,2-di-methylpropyldiphenyl phosphate, n-hexyl diphenyl phosphate, n-heptyl diphenylphosphate, n-octyl diphenyl phosphate, 6-methylheptyl diphenylphosphate, Z-ethylhexyl diphenyl phosphate, 3,5,5- trimethylhexyldiphenyl phosphate, ethyl ditolyl phosphate, n-hexyl ditolyl phosphate,2-methylpentyl ditolyl phosphate, 2-ethylbutyl ditolyl phosphate,n-octyl ditolyl phosphate, 2-ethylhexyl ditolyl phosphate,3,5,5-trimethylhexyl ditolyl phosphate, n-decyl ditolyl phosphate,2-ethy1hexyl phenyl cresyl phosphate, lauryl phenyl cresyl phosphate,2-butylhexyl ditolyl phosphate, n-dodecyl ditolyl phosphate and2-butyloctyl ditolyl phosphate. The preferred of the above-mentionedcompounds is 2-ethylhexyl diphenyl phosphate.

The selected film-forming halogen-containing polymer and theorgano-phosphorous compound are compounded by conventional methods intoa solution, organosol, latex, comprising about 35% to about 70%non-volatiles or plastisol. For example, an emulsion of the plasticizerin water is prepared and subsequently stirred into the latex by highspeed agitation. A suitable emulsifying agent may be employed to promoteemulsification of the two immiscible phases. Although the proportion ofplasticizer to be used will vary somewhat with the effectivenessthereof, preferably, the organo-phosphorous compounds constitute about15% to about 60% b weight of the two nonvolatile materials. When asolution of film-forming halide polymer is employed, the amount ofpolymer will normally constitute about 15-35% by weight thereof.

The coating material (latex, plastisol, organosol, or solution) isapplied to the topside of the carpet backing. Care is taken that thecoating material is uniformly spread by conventional techniques in theform of a thin film in sufficient amount that on a dry basis or moreaccurately on a non-volatile content basis the add-on weight is about1.5 to 10 ounces per square yard of backing. After the backing has beenproperly coated, it is cured by known procedures, preferably in an ovenby the application of heat. The coating material should be viscous togive a proper coating on the backing without penetrating the backing toan undesirable extent. Thickening agents may be added if needed. Ifdesired, the coating of the filmforming, halogen-containing polymer mayalso be applied by suitable techniques, e.g. by spreading an organosolcoating, by heat sealing or glueing a suitable plasticized film onto thebacking, by solution application, spreading a foamed or unfoamedplastisol, and the like.

The pile is woven in, tufted through, flocked, knitted or in some othermanner embedded in the cured backing material. Yarn loops on the topface of the backing may or may not be cut in whole or in part asdesired. The loops may have the same height or have various heights inthe pile.

The fibrous pile can be composed of any of the usual synthetic filamentsor fibers or blends or mixtures thereof employed in carpet manufactureincluding: 1) Polyamides, also called nylon which is a. manufacturedfiber of any long chain synthetic polycarbonamide having recurring amidegroups as an integral part of the polymer chain; specific examplesinclude polymeric hexamethylene adipamide (nylon-66), polymeric 6-aminocaproic acid (nylon-6), polymers of 1,4-cyclohexanedimethylamine andadipic acid (CBMA-6) or dodecanedioic acid (CBMA-l2), polymers ofbis(para-aminocyclohexylmethane) and azelaic acid (PACM-9) ordodecanedioic acid (PACM-l2). (2) Polyesters, made of a fiber-formingsubstance of any long chain synthetic polymer composed of at least byweight of an ester of a dihydric alcohol and terephthalic acid, specificdihydric alcohols including ethylene glycol, 1,4-butanediol and1,4-cyclohexanedimethanol. (3) Modacrylics made of a fiber-formingsubstance composed of less than 85% but at least 35% by weight ofacrylonitrile units. (4) Polyolefins made of a fiber-forming substancecomposed of at least 85% ethylene, propylene or other olefin units.

Materials, such as polyalkoxylated compounds, may be incorporated in thefilaments or fibers to lower the propensity of buildup of staticelectricity thereon. The compounds will normally be finely dispersed asa separate phase in the polymer in an amount of l-15 based on the weightof the filaments or fibers. A preferred additive is a polyalkoxylatedtriglyceride of a saturated hydroxy fatty acid having 12-30 carbon atomsas disclosed in US. Pat. 3,388,104. The polyoxyalkylene portion of theglyceride should be in the molecular Weight range of 1000 to 30,000 andmay be ethoxy, propoxy, etc. Alternatively, po1y(alky1ene ethers) may beincorporated in the pile fibrous material. These additives are ethyleneoxide, propylene oxide, etc. condensation products. Also,polyalkoxylated saturated di-fatty alkyl amines wherein the polyalkoxyportion has a molecular weight of about 2000 to 22,000 and wherein thetwo fatty alkyl substituents have 10 to 30 carbon atoms are useful.Combination of additives are contemplated. The presence of suchadditives in nylon-66 yarn in antistatic quantities normally renders theyarn non-self-extinguishing to a flame, Whereas otherwise the yarn wouldbe self-extinguishing to an applied flame.

The following examples illustrate the invention.

EXAMPLE I (a) Nylon-66 yarn containing 7.5% dispersed polyethoxylatedglyceryl tri(hydroxystearate) (200 mols of ethylene oxide per mole ofglyceryl trihydroxy stearate) as disclosed in US. Pat. 3,388,104 andcomposed of 136 filaments with a flat drawn denier of 2460 was texturedby gear crimping as disclosed in US. Pat. 3,024,517. Three separate endsof this yarn were loosely plied together. The resulting ply yarn wastufted into a 10 ounce (Weight per square yard) plain weave jute carpetbacking. The pile height of the yarn was 1% inch. The number of tuftsper square inch averaged 7.8. A hexamethylenetetramine pellet weighing0.15 gram was placed in the center of a 4-inch square sample of thecarpet structure and was ignited. The flame ignited the pile fabric andwas propagated along the pile of tufted fabric. Hence, the carpet wasnot flame retardant.

(b) A polyvinyl chloride latex composed of an aqueous emulsion ofpolyvinyl chloride and 2-ethylhexyldiphenyl phosphate was prepared. Forparts by dry weight of polyvinyl chloride there were 85 parts by dryweight 2-ethylhexyldiphenyl phosphate. Together these two ingredientsgave the emulsion a 58.7% non-volatile content. The latex was evenlyspread along the top side of a 10 ounce plain weave jute carpet backing.The addon Weight of polyvinyl chloride and 2-ethylhexyldiphenylphosphate on a dry basis was 3.9 ounces per square yard. This coatedbacking was cured in a hot air oven at C. for 25 minutes. The pliednylon-66 yarn as described above in this example was tufted into thecured backing. In like manner, the pile height of the yarn Was 1% inchesand the number of tufts per square inch averaged 7.8. Ahexamethylenetetramine pellet weighing 0.15 gram was placed in thecenter of a 4-inch square sample of the carpet structure and wasignited. After the pellet had burned, essentially no additional burningof pile fabric occurred. The charred area was confined to a small area,about inch in diameter adjacent the position of the pellet. Hence, thecarpet was regarded as flame retardant.

EXAMPLE II (a) The unbacked carpet of Example I(a) was blankdyed, i.e.subjected to normal carpet dyeing conditions without the presence of adyestuff. The blank-dyeing procedure consisted of boiling for one hourin an aqueous bath containing (on fiber weight) 2% trisodium phosphate,2% ammonium sulfate, 1%% of surface active agent with total liquid:fiberratio of 40:1 by Weight. The sample was then rinsed in cold water, driedin a hot air oven for 2 hours at 105 C., and desiccated over silica gelfor 1 hour. The carpet was then tested using the hexamethylenetetraminepellet as described in Example 1(a). The flame ignited the fabric andpropagated. Hence, the carpet was not flame-retardant.

(b) The unbacked carpet of Example I(b), where the add-on was 3.9 oz./sq. yd. of polyvinyl chloride and 2- ethylhexyldiphenyl phosphate, aftertufting was blankdyed, rinsed, dried and desiccated as in Example II(a).The carpet was then tested using the hexamethylenetetramine pellet asdescribed in Example 1(a). The flame did not propagate along the tufts;and, the carpet was regarded as flame-retardant. Therefore, theimprovement of the present invention persists even after the carpet issubjected to normal dyeing conditions.

(c) The carpet was the same as that in Example II(b) above, except thatthe add-on was 5.1 oz./sq. yd. of polyvinyl chloride and 2ethylhexyldiphenylphosphate. The carpet was treated the same as that inExample II(b) above. This carpet was tested in a similar fashionincluding blank-dyeing and was found to be flame-retardant.

EXAMPLE III (a) Example II(a) was repeated except that instead of thejute backing a non-woven polypropylene backing reinforced with a warp ofspun polyethylene terephthalate threads was employed. The backingweighed 6.5 ounces per square yard and was commercially available underthe name Loktuft from Phillips Fibers. It was found that the resultingcarpet structure was not flame-retardant when subjected to the pellettest.

(b) Example II(a) was repeated except that the nonwoven polypropylenebacking (Loktuft) was used and the add-on weight of the polyvinylchloride and Z-ethylhexyldiphenyl phosphate was 3.8 ounces per squareyard. Again it was found that using the pellet test the resulting carpetstructure was flame-retardant.

(c) When the amount of the 100/85 mixture of polyvinyl chloride andZ-ethylhexyldiphenyl phosphate was reduced below 2 ounces per squareyard, the carpet of Example II(a) was found not to be flame-retardant.Specifically, Example III(b) was repeated except that the add-on ofhalide polymer-phosphate mixture was reduced to 1.1 ounces per squareyard. At this level the carpet failed the pellet test.

EXAMPLE IV (a) A solution of grams of polyvinyl chloride copolymercontaining a very minor amount of a monomer other than vinyl chloride(analysis: 47.2% Cl) and 10 grams of an organo-phosphate compound of theformula where six Xs are chlorine and four Xs are bromine was prepared.Eighty grams of chlorobenzene was used as the solvent. Nylon-66 yarn ofthe type described in Example I(a) was tufted into a 10 ounce plainweave jute carpet backing. Prior to tufting the polyvinylchloride-organo-phosphate solution was added to one side of the jutefabric which then was dried to provide an add-on weight of polyvinylchloride-organo-phosphate of 2.0 ounces per square yard on a dry basis.The pile height of the yarn was 1% inches and the number of tufts persquare inch was 7.8. A hexamethylenetetramine tablet weighing 0.15 gramwas placed in the center of a 7 inch square sample of the carpetstructure and was ignited. The flame was not propagated and the charredarea was restricted to a small area. adjacent the location of thetablet. Hence, the carpet was flame-retardant.

(b) Example IV(a) Was repeated except that the organo-phosphate compoundwas slightly different from a chemical structure standpoint. In thisinstance the phosphate compound had the following structure (M) 011201(I? (ClCH CHzOMP OCHz--(. .O P(OCH2CH2Cl)1 When the resulting structurewas subjected to the pellet test, it was again found that the flame wasnot propagated and the charred area was restricted to a small areaadjacent the location of the pellet.

EXAMPLE V An emulsion of 65.0 grams of tris(2,3-dibromopropyl)phosphate, 1.25 grams of oleic acid, 0.35 gram NH OH (28% by weight),and 33.4 grams water was prepared with a high shear mixing device. Thisemulsion was added to and mixed with 252 grams of an aqueous emulsion ofa polyvinyl chloride and Z-ethylhexyl diphenyl phosphate (35 weightparts of phosphate compound to weight parts of vinyl chloride polymer).A piece of 9-inch square of Loktuft carpet backing Weighing 7.3 gramswas treated on the upper face side with the resulting mixture ofemulsions and cured 40 minutes at 106 C. in a forced air oven to give anadd-on weight of 5.3 ounces per square yard. This treated backing wastufted with the type of yarn described in Example I(a) except in thisinstance the yarn was a single end of 3690 total denier and the pileweight was 23.5 ounces per square yard. This carpet fabric was latexedon the underside with 26 ounces per square yard of a compoundedcarboxylated styrene butadiene rubber latex. The rubber latex is sold byTextile Rubber Co., under the name L-1254 latex. A secondary backing ofLoktuft as applied and the resulting carpet composite was cured for 40minutes at 106 C. As above, a small hexamethylenetetramine tablet wasplaced in the center of the carpet sample and was ignited. The flame wasnot propagated; thus, the carpet was flameretardant.

EXAMPLE VI (a) This example shows that vinylchloride polymer without anorgano-phosphate compound when applied to a jute fabric will notsufficiently flame retard a nylon pile. A PVC latex consisting of 38.6%vinylchloride polymer (97% vinylchloride and 3% vinyl acetate) wasapplied evenly to the top surface of jute carpet backing fabric as inExample I(b) and cured at C. for 20 minutes. The add-on weight of vinylchloride polymer on a dry basis was 5.0 ounces per square yard Nylon 66yarn of the type described in Example I(a) was tufted into the treatedjute fabric at 2.8 rows per inch and 2.8 stitches per inch, with a pileheight of 1% in. A hexamethylenetetramine tablet weighing 0.15 gram wasplaced in the center of a 7 in. square sample of the carpet structureand was ignited. The flame was propagated along the surface of thecarpet sample for a period of 9 minutes, covering a large area of thesample before it was extinguished. Hence, the carpet was notflame-retardant.

(b) A PVC latex consisting of 38.6% vinyl chloride polymer (97% vinylchloride and 3% vinyl acetate) was applied evenly to the top surface ofjute carpet backing fabric as in Example 1(b) and cured at 150 C. for 20minutes. The add-on weight of vinyl chloride on a dry basis wasincreased to 11.3 ounces per square yard. Nylon 66 yarn of the typedescribed in Example 1(a) was tufted into the treated jute at 2.8 rowsper inch and 2.8 stitches per inch, with a pile height of 1 A in. Ahexamethylenetetramine tablet weighing 0.15 gram was placed in thecenter of a 7 inch square sample of the carpet structure and wasignited. The flame was propagated along the surface of the sample for aperiod of 9 minutes; the burn covered a large area of the sample beforeit was extinguished. Hence, the carpet was not flame-retardant eventhough a rather large amount of vinyl chloride polymer was coated on thetop side of the jute fabric.

EXAMPLE VII A piece of Loktuft carpet backing was tufted with yarn as inExample I(a) (except this yarn was a single end of 3690 total denier) ata weight of 23.5 ounces per square yard. The carpet fabric was latexedon the underside with 26 ounces per square yard of L-1254 latex (TextileRubber Company) above-described, and a secondary backing of Loktuft wasapplied; the carpet sample was cured 40 minutes at 106 C. Ahexamethylenetetramine tablet was placed in the center of the sample andignited. The flame was propagated along the surface of the sample for aperiod of 10 /2 minutes; the burn covered a large area of the samplebefore it was extinguished. Hence, carpet constructed of nylon-66 pileand a nonwoven thermoplastic backing without the coating ofhalogencontaining polymer plus organo-phosphorous compound is notflame-retardant.

EXAMPLE VIII An aqueous emulsion latex of 35 parts of dioctyl phthalateper 100 parts of film-forming polyvinyl chloride was prepared, thepercent solids in the latex being 57. Dioctyl phthalate is aconventional plasticizer for vinyl chloride polymer but contains nophosphorous. The latex was evenly spread along the top side of a 10ounce plain weave jute carpet backing. The add-on weight of the latexsolids was 4 ounces per square yard. The coated backing was cured in ahot air oven at 105 C. for 25 minutes and then cooled. The plied nylon66 yarn as described in Example 1(a) was tufted to provide a shagconstruction. The carpet sample was tested for flame-retardancy usingthe above-described pellet ignition test. It was noted that the flamepropagated along the tufts of the carpet. This shows that nylon pileshag yarn in a jute backing, the top side of which is coated with avinyl chloride polymer but no organo-phosphate plasticizer is notflameretardant.

EXAMPLE IX (a) A 10 ounces per square yard jute fabric was tufted to thefollowing specifications: 2.8 rows/in., 4.2 stitches/ in., 1 /2 in. pileheight, 26 ounces per square yard of heat-set, 1% turn per inch (t.p.i.)twist, 3690 total denier nylon 66 yarn of three types. The three typeswere (1) a nylon-66 yarn containing 7 /z% dispersed polyethoxylatedglyceryl tri(hydroxy stearate) as described in EX- ample I(a); (2) anylon-66 yarn as in (1), but containing in addition a small amount ofdisodium-disulfobenzoic acid for cationic dyeability; and (3) a yarn of94% nylon-66 and 6% nylon-6 copolymer containing /2% of thejust-mentioned stearate. The tufted fabric was blankdyed in a standardapparatus. The fabric was first washed in a bath containing 2% sodiumhydrosulfite and 1% trisodium phosphate (on fiber weight) with 40:1liquor: fiber ratio for 15 minutes at 49 C. The fabric was rinsed andthen blank-dyed for one hour at 100 C. in a bath containing 1%surfactant (on fiber weight) with monosodium phosphate added to bring pHto 6.0. The fabric was rinsed and dried in a hot air tumble dryer. Itwas hand-latexed with 26 ounces per square yard L-1254 latex (TextileRubber Company) and cursed at 130 C. for 25 minutes. No secondarybacking was applied.

Eight 81 square inch (9 in. x 9 in.) samples were tested according toASTM-2859-70T; 8 of 8 failed the test, hence the carpet was notflame-retarded.

EXAMPLE X A 10 ounces per square yard jute fabric carpet backing wastreated on the top side with 5.1 ounces per square yard on a dry basisof the polyvinyl chloride and 2- ethylhexyldiphenyl phosphate latex. For100 parts by weight of polyvinyl chloride, there was 85 parts by dryweight 2-ethylhexy1diphenyl phosphate; together these two ingredientsgave the emulsion a 58.7% non-volatile content. This coated jute backingwas tufted as described in Example IX(a) above and then blank-dyed anddried as above; it was then hand-latexed with 26 ounces per square yardof L-1254 latex as in Example IX(a). No secondary backing was applied.Eight 81 square inch (9 in. x 9 in.) samples were tested according toASTM- 2859-70T; 7 out of 8 passed; thus the carpet was flameretardantaccording to this carpet flammability test.

EXAMPLE X1 (a) A 5.5 ounces per square yard Loktuft polypropylene carpettufting fabric was tufted to the following specification: 2.8 rows/in,4.2 stitches/in, 25 ounces per square yard of heat-set, 1% t.p.i. twist,3690 total denier nylon 66 yarn of the type described in Example IX(a)with a 1 /2 inch pile height. The tufted fabric was blank-dyed, anddried as described in Example IX(a). It was then hand-latexed on theback side with 26 ounces per square yard L-l254 latex (Textile RubberCompany) and cured at 120l30 C. for 25 minutes. A secondary backing of5.5 ounces per square yard Loktuft was then applied.

1 ight 81 square inch (9 in. x 9 in.) samples were tested according toASTM285970T; 2- of 8 failed the test, hence the carpet was notcompletely flame-retardant and failed to pass this particular test forcarpet flammability.

(b) A polyvinyl chloride latex composed of an aqueous emulsion ofpolyvinyl chloride and Z-ethylhexyldiphenyl phosphate was prepared as inExample I(b); for parts by 'weight of polyvinyl chloride; there was 85parts by dry weight 2-ethylhexyldiphenylphosphate. The latex was evenlyspread on the top side of a 4.5 ounces per square yard Loktuftpolypropylene carpet backing fabric. The add-on weight of polyvinylchloride and Z-ethylhexyldiphenyl phosphate on a dry basis was 3.0ounces per square yard. This coated Loktuft polypropylene carpet backingwas tufted according to the specification given in Example XI(a) above,and this carpet was blank-dyed and dried as in Example IX(a). The carpetfabric was hand-latexed as in Example XI(a) above, and a secondarybacking of 5.5 ounces Loktuft was then applied. Eight 81 square inch (9in. x 9 in.) samples were tested according to ASTM-2859-70T; 8 passedand none failed the test; hence the carpet was suflicientlyflame-retarded by the coating on the upper surface of the primarybacking to permit the carpet to pass this particular test for carpet,whereas the carpet in Example XI(a) above made with the uncoated primarybacking failed.

(c) A 6.5 ounces (weight per square yard) Loktuft polypropylene carpetbacking fabric was treated on the top side with 7.1 ounces per squareyard on a dry basis of the polyvinyl chloride and 2-ethylhexyldiphenylphosphate latex described in Example XI(b) above. This coated Loktuftbacking was tufted as described in Example XI(a) above and thenblank-dyed and dried as in Example X(a). The carpet fabric washand-latexed as in Example XI(a) above, and a secondary backing wasapplied as in Example XI(b) above. Eight 81 square inch (9 in. x 9 in.)samples were tested according to ASTM- 9 2859-70T; 8 out of 8 passed,sufliciently flame-retarded by the coating on the upper surface of theprimary backing to permit the carpet to pass this particular test forcarpet flammability, whereas the carpet made with the uncoated primaryLoktuft backing failed.

EXAMPDE XII (a) A 3.4 ounces per square yard nylon 66 filamentspunbonded nonwoven fabric made by Monsanto Company and named Cerex wastufted to the following specifications: 2.8 rows/in., 4.2 stitches/in, 1/2 in. pile height, 26 ounces per square yard of heat-set, 1% t.p.i.twist yarns of the type described in Example IX(a). This carpet waswashed as described in Example IX(a), blankdyed as described in ExampleII(a), and dried.

Eight 81 square inch (9 in. x 9 in.) samples were handlatexed withTextile Rubber Companys L-l254 latex, and secondary-backed with Cerexnonwoven product. Eight samples were then tested according to ASTM-2859-7OT; of 8 failed. Hence, the carpet was not flameretarded.

(b) A polyvinyl chloride latex composed of an aqueous emulsion ofpolyvinyl chloride and Z-ethylhexyldiphenyl phosphate was prepared as inExample X. For 100 parts by dry weight of polyvinyl chloride, there was85 parts by dry weight 2-ethylhexyldiphenyl phosphate. The latex wasevenly spread along the top side of a 3.4 ounces per square yard Cerexfabric. The coated backing was cured in a hot air oven. The add-onweight of polyvinyl chloride and Z-ethylhexyldiphenyl phosphate on a drybasis was 3.5 ounces per square yard. This coated backing was tufted tothe following specifications: 2.8 rows/in., 4.2 stitches/in., 1 /2 in.pile height, 26 ounces per square yard of heat-set, 1% t.p.i. twistyarns of the type described in Example IX(a). This carpet was stripped,blank-dyed, and dried as in Example XII(a).

Eight 81 square inch (9 in. x 9 in.) samples were handlatexed withTextile Rubber Companys L-l254 latex, and secondary-backed with Cerexfabric. Eight samples were then tested according to ASTM-2859-70T; 8 of8 passed.

The charred area was confined to a small area, about 1% in. diameteradjacent to the position of the pellet. Hence, the carpet was regardedas flame-retardant.

(c) A polyvinyl chloride latex composed of an aqueous emulsion ofpolyvinyl chloride and 2-ethylhexyldiphenyl phosphate was prepared. For100 parts by dry weight of polyvinyl chloride, there was 85 parts by dryweight 2- ethylhexyldiphenyl phosphate. The latex was evenly spreadalong the top side of a 3.4 ounces per square yard Cerex carpet backing.The coated backing was cured in a hot air oven. The add-on weight ofpolyvinyl chloride and 2-ethylhexyldiphenyl phosphate on a dry basis was5 ounces per square yard. This coated backing was tufted to thefollowing specifications: 2.8 rows/in, 4.2 stitches/ in., 1 /2 in. pileheight, 26 ounces per square yard of heatset, 1% t.p.i. twist yarn ofthe type described in Example IX(a). This carpet was stripped,blank-dyed, and dried as in Example XII(a).

Eight 81 square inch (9 in. x 9 in.) samples were handlatexed withTextile Rubber Companys L-l254 latex, and secondary-backed with Cerexfabric. Eight samples were then tested according to ASTM-2859-70T; 8 of8 passed.

The charred area was confined to a small area, about 1% in. diameteradjacent to the position of the pellet. Hence, the carpet was regardedas flame-retardant.

EXAMPLE XIH (a) Nylon yarn of the type described in Example I(a) wastufted into a 4 ounces per square yard Loktuft polypropylene carpetbacking. The yarn was 4920 total denier and was tufted to a pile heightof 1% in. The number of tufts per square inch was 7.8. The 5 in. x 5 in.square tufted area was then latexed on the under side with TextileRubber Companys L-1254 latex at a level of 26 ounces per square yard;the latex was cured for 20 min. at 120 C. The samples were then testedaccording to the proposed ASTM-285970T procedure except for size ofsample. In two of four samples tested, the flame ignited the pile fabricand was propagated along the pile of tufted fabric. Hence, the carpetwas not flame-retardant.

(b) A 4 ounces per square yard Loktuft polypropylene carpet backing wascoated on the upper side with 2.2 ounces per square yard of vinylchloride polymer-containing latex (97% vinyl chloride plus 3% vinylacetate). The pretreated backing was cured 20 minutes at 120 C. Nylonyarn like that used in Example XIII (a) above was tufted into thepretreated backing so that the tufts and PVC coating were face up. Thepile height of the yarn was 1% in.; the number of tufts per square inchwas 7.8. The 5 in. x 5 in. square tufted area was then latexed withTextile Rubber Companys L-l254 latex at a level of 26 ounces per squareyard. The latex was cured for 20 minutes at 120 C. The samples were thentested according to the proposed ASTM-2859-70T procedure except for thesize of the carpet samples. Eight of eight passed with an average burntime of 2 minutes 3 seconds. Thus, the polyvinyl chloride coating on theupper face side of the primary backing greatly increased theflameretardancy of this carpet wherein the backing is a thermoplasticmaterial.

(c) A 4 ounces per square yard Loktuft polypropylene carpet backing wascoated on the face side with 4.7 ounces per square yard of a latexconsisting of 38.6% vinylchloride polymer (97% vinyl chloride and 3%vinyl acetate). The pretreated backing was cured for 20 minutes at 120C. Nylon yarn like that used in Example XIII(a) above was tufted intothe pretreated backing so that the tufts and PVC coating were face up.The pile height of the yarn was 1% in., the number of tufts per squareinch was 7.8. The 5 in. x 5 in. square tufted area was then latexed withTextile Rubber Companys L-1254 latex at a level of 26 ounces per squareyard. The latex coated structure was cured for 20 minutes at 120 C. Thesamples were then tested according to the proposed ASTM-2859- 7OTprocedure except for the size of the carpet samples. Eight of eightpassed with an average burn time of 2 minutes 11 seconds. Thus, thepolyvinyl chloride coating on the upper face side of the primary backinggreatly increased the flame-retardancy of this carpet.

EXAMPLE XIV A solution of 10 grams PVC copolymer (analysis: 47.2%chlorine) and 10 grams triphenyl phosphate in grams chlorobenzene wasprepared and applied evenly to the top surface of jute as in ExampleI(b) and cured at 136 C. for 30 minutes. The add-on weight of PVCtriphenyl phosphate on a dry basis was 4.2 ounces per square yard. Nylon66 yarn of Example I(a) was tufted into the treated jute at 2.8 rows/in.and 2.8 stitches/in., and a pile height of 1% in. Ahexamethylenetetramine pellet weighing 0.15 gram was placed in thecenter of a 5 in. square sample of the carpet structure and was ignited.The flame was not propagated and the charred area was restricted to asmall area adjacent to the position of the pellet. Hence, the carpet wasflame-retardant.

EXAMPLE XV A polyvinyl chloride plastisol consisting of parts vinylchloride polymer (97% vinyl chloride and 3% vinyl acetate), 90 partsSanticizer 140 (cresyldiphenylphosphate), 3 parts epoxidized soy beanoil, 2 parts (Ba, Cd soap-heat stabilizer), and 3 parts Sb O was appliedevenly to the top surface of jute, as in Example I(b), and cured at C.for 20 minutes. The add-on weight of plastisol on a dry basis was 6.8ounces per square yard. Nylon yarn of Example I(a) was tufted into thetreated jute and a hexamethylenetetramine pellet was placed on thesample and ignited as in Example XIV. The flame 1. 1 was not propagatedand the charred area was restricted to a small area adjacent to theposition of the pellet. Hence, the carpet was flame-retardant.

EXAMPLE XVI A 50% aqueous emulsion latex of 35 parts of tricresylphosphate per 100 parts of a 15/ 85 vinyl chloride/ vinylidene chloridecopolymer was prepared. The latex was stabilized with 2% anionicemulsifier. This latex was evenly spread along the top side of a 3.4ounces per square yard nonwoven nylon 66 fabric (Cerex by MonsantoCompany St. Louis, Mo.). The coated backing was cured in a hot air ovenat 105 C. for 25 minutes and then cooled. The plied nylon 66 yarn asdescribed in Example I(a) was tufted to provide a shag construction. Thecarpet sample was tested for flame-retardancy using the abovedescribedpellet ignition test. It was observed that the charred area was confinedto a small area.

EXAMPLE XVII (a) A 5 inch square piece of jute carpet backing was tuftedwith polyethylene terephthalate polyester spun staple yarn individualdenier, total denier 6984) at a weight of 30 ounces per square yard, at2.8 roWs per inch and 4.2 stitches per inch. The sample was curedminutes at 150 C. A hexamethylenetetramine tablet was placed in thecenter of the sample and ignited. The flame was propagated along thesurface of the sample for a period of 8 minutes before it wasextinguished, burning a large area of the sample. Hence, the carpet wasnot flame-retardant.

(b) A 5 inch square piece of jute carpet backing was treated on the facesurface as in Example I(b), with :1 solution of 10 grams vinyl chloridepolymer (97% vinyl chloride, 3% vinyl acetate) and 10 grams triphenylphosphate in 80 grams chlorobenzene, and cured at 150 C. for 20 minutes.The add-on weight of PVC/triphenyl phosphate was 4.9 ounces per squareyard. The sample was tufted with polyester yarn as in Example XVII(a),cured 20 minutes at 150 C., and a hexamethylenetetramine tablet wasplaced in the center of the sample and ignited. The flame was notpropagated and the charred area was restricted to a small area adjacentto the position of the tablet. Hence, the carpet was flameretardant.

EXAMPLE XVIII (a) A 5 inch square area of Loktuft polypropylene carpetbacking was tufted with polyester yarn of the type described in 'ExampleXVII(a), exactly as in Example XVII(a), at a weight of ounces per squareyard. A secondary Loktuft backing was latexed with 26 ounces per squareyard of L-l254 latex and married to the tufted backing with hand press;the sample was then cured 40 minutes at 106 C. A hexamethylenetetraminetablet was placed in the center of the carpet sample and ignited. Theflame was propagated along the surface of the sample for a period of 6minutes before it was extinguished, burning a large area of the sample.Therefore, the carpet was not flame-retardant.

(b) A 5 inch square area of Loktuft carpet backing was treated on theface surface, as in Example I(b), with a solution of 10 grams vinylchloride polymer (97% vinyl chloride, 3% vinyl acetate) and 10 gramstriphenyl phosphate in 80 grams chlorobenzene, and cured at 106 C. for20 minutes. The add-on weight of PVC/triphenyl phosphate was 1.3 ounceper square yard. The sample was tufted with polyester yarn and backedwith a secondary backing of Loktuft, as in Example XVIII(a), and thencured 40 minutes at 106 C. A hexamethylenetetramine tablet was placed inthe center of the sample and ignited. The flame was not propagated andthe charred area was restricted to a small area adjacent to the positionof the tablet. Therefore, the carpet was flameretardant.

12 EXAMPLE XIX (a) A 5 inch x 5 inch square area of Loktuftpolypropylene carpet backing was tufted With 3690 denier nylon 66 yarnas described in Example I at a weight of 22 ounces per square yard. Asecondary Loktuft backing was latexed with 26 ounces per square yard ofL-1254 latex and married to the primary backing; the sample was thencured 40 minutes at 106 'C. A hexamethylene tablet was placed in thecenter of the sample and ignited. The flame was propagated along thesurface of the sample for a period of 11 minutes before it wasextinguished, burning a large area of the sample. Therefore, the carpetwas not flame-retardant.

(b) A 5 inch x 5 inch square area of Loktuft carpet backing was treatedon the face surface, as in Example I(b), with 15% vinyl chloride,vinylidene chloride copolymer latex and cured 40 minutes at 106 C. Theadd-on weight on a dry basis was 6.9 ounces per square yard. The samplewas tufted with nylon 66 yarn as described in Example I and latexed withL-l254 as in Example XIX(a) and cured 40 minutes at 106 C. Ahexamethylene tetramine tablet was placed in the center of the sampleand ignited. The flame was not propagated and the charred area wasrestricted to a small area adjacent to the position of the tablet.Therefore, the carpet was flame-retardant.

EXAMPLE XX A PVC plastisol consisting of parts vinyl chloride polymer(97% vinyl chloride and 3% vinyl acetate), 60 parts n-butyl benzylphthalate and 30 parts dioctyl phthalate, was applied evenly to the topsurface of jute carpet backing fabric as in Example I(b), and cured atC. for 20 minutes. The add-on weight of the plastisol on a dry basis was26.1 ounces per square yard. Nylon yarn of the type described in ExampleI(a) was tufted into the treated jute. 1A hexamethylenetetramine tabletwas placed on the sample and ignited. The flame was propagated along thesurface of the sample for a period of 9 minutes 36 seconds; the burncovered a large area of the sample before it was extinguished. Hence,the carpet with a jute backing even coated with vinyl chloride polymerplus an organic PVC plasticizer (not containing phosphorous) was notflame-retardant.

We claim:

1. A flame-retardant carpet structure comprising:

(a) yarn pile of synthetic filaments or fibers made of a polymerselected from the group consisting of polyester, polyamide, andpolyolefins;

(b) a primary carpet backing having a top surface and an undersidesurface into which the pile yarn is placed to present a pile surfaceextending from the top surface of the said backing;

(c) a coating of a film-forming polyvinyl chloride polymer containing awater insoluble organic phosphate ester having the formula wherein R Rand R are the same or different monovalent radicals selected from thegroup consisting of an aliphatic radical of 1-24 carbon atoms with up tothree double bonds between the carbon atoms, an alicyclic radical and anaromatic radical, said phosphate ester constituting 15 to 60 percent byweight of the coating, said coating applied to and confined essentiallyto the top surface of the backing without substantial penetration of theyarn pile of 13 the coating, the weight of the coating being 1.5 to 10ounces per square yard of backihg on a nonvolatile content basis.

2. The carpet as defined in claim 1 wherein the backing is selected fromthe group consisting of a plain weave jute structure, non-woven nylon,and non-woven polyolefin.

3. The carpet as defined in claim 1 wherein the phosphate ester isZ-ethylhexyl diphenyl phosphate.

4. The carpet as defined in claim 1 wherein the phosphate ester istriphenyl phosphate.

5. The carpet as defined in claim 1 wherein the phosphate ester iscresyl diphenyl phosphate.

14 References Cited UNITED STATES PATENTS 3,348,992 10/1967 Cochran161-67 5 3,041,707 7/1962 Perri "161- 67 3,535,192 10/1970 Gamble 161-67 FOREIGN PATENTS 1,161,078 8/1969 Great Britain 161403 10 WILLIAMJ. VAN BALEN, Primary Examiner US. Cl. X.R.

